PROJECT SUMMARY I am an environmental epidemiologist with a primary research interest in the role of developmental windows, joint impact of multiple exposures and molecular mechanisms through which prenatal/early-life exposure to chemical and non-chemical stressors influence children's lung development. The goal of this proposal is to obtain training in the skills needed to continue to build my academic career by linking ambient air pollution and stress to lung development and to identify biomarkers of early biological effects of these exposures. Formal coursework and the expert mentorship of Drs. Rosalind Wright, Andrea Baccarelli, Robert Wright, Maria Martha Tellez-Rojo, Brent Coull, Alfin Vicencio and Allan Just will enable me to acquire the knowledge and skills necessary to become an independent transdisciplinary researcher. This training will allow me to achieve my long-term career goals: taking the lead in studying respiratory health in the ongoing Mexico City PROGRESS cohort in order to examine these and other environmental exposures, their biological mechanisms, and the subsequent effects on lung function and asthma risk longitudinally as these children grow up. All relevant exposure and covariate data exist in an existing well-phenotyped pregnancy cohort [Programming Research in Obesity, Growth, Environment and Social Stressors (PROGRESS) study leveraged herein. I will add respiratory phenotyping to the cohort. Specifically I will 1) train in state of the art stress assessment as well as fetal and early childhood lung development and physiology with Dr. RJ Wright, 2) train in early biologic markers of oxidative stress in Dr. Baccarelli's lab, 3) train in advanced statistical methods that temporal resolved daily to weekly assessed exposure data to definitively identify susceptibility windows to enhance our ability to find effects and identify vulnerable groups with Dr. Brent Coull, 4) integrate research on stress, air pollution and molecular epidemiology through interactions with my mentorship team to become an interdisciplinary scientist and 5) translate the research and administrative training I receive to establish myself as a independent investigator with a tenure track faculty position and to position myself for a future R01. This proposal will address gaps in the understanding of timing and mechanism through which air pollution exposure and stress affect respiratory health in early childhood. This proposed research and training plan builds the foundation for an independent research career that aims to clarify the mechanisms through which ambient air pollution and stress are associated with respiratory morbidity and ultimately inform intervention/prevention efforts. This study is also highly cost effective as we leverage the resources of the PROGRESS study with existing biospecimens, environmental and psychosocial stress data.